What is blood in urine? -  This refers to the presence of blood cells in urine. Normally, the kidneys filter blood to produce urine. During this process, blood is returned to the blood vessels while waste products of the body is filtered into urine and passed out of the body. During this process, however, some red blood cells may escape into the filtered urine.

So, it is not uncommon to find some red blood cells in urine but this is usually in quantity that is too small to alter the colour of urine or seen by unaided eyes. This small quantity of blood is detected only during investigation. When blood is obvious in urine by turning it pink or red, it may point to certain disease conditions. 

What are the causes of blood in urine?

The possible causes of blood in urine include:

1. Stones in urinary tract: kidney stone, ureteric stone and bladder stone.
2. Bladder infestation (e.g. schistosomiasis)
3. Urinary tract infection (UTI)
4. Kidney infection (pyelonephritis)
5. Bladder infection / inflammation (cystitis)
6. Enlarged prostate (benign prostatic hypertrophy)
7. Injury to urinary tract (e.g. during surgery or contact sports like hockey, football, boxing etc)
8. Menstruation
9. Endometriosis
10. Chronic kidney disease
11. Sickle cell disease
12. Cancers along the urinary tract, including: kidney, bladder, ureteral, urethral and prostate cancers.

What symptoms are associated with passage of blood in urine?

Passage of blood in urine may not be associated with any symptom, such as that associated with menstruation or endometriosis. Symptoms that may be associated with passage of blood in urine include:

1. Frequent urination
2. Pain when passing urine
3. Urinary urgency (a strong need to pass urine)
4. Fever
5. Nausea and vomiting
6. Lower abdominal / back pain
7. Right or left loin pain

What is the treatment for passing blood in urine?

Treatment depends on the cause:

1. Infection – Antibiotics
2. Menstruation – No treatment needed
3. Schistosomiasis – Albendazole, mebendazole
4. Enlarged prostate – Alpha blockers; 5-alpha-reductase inhibitors; surgery
5. Sickle cell disease – Hydroxyuria, pain relievers and antibiotics
6. Chronic kidney disease – Erythropoietin therapy for anaemia and treatment for other associated conditions such as high blood pressure, high cholesterol etc.
7. Endometriosis – Hormone-related treatment
8. Cancer – Treatment may include one or a combination of the following: surgery, chemotherapy, radiation therapy, immunotherapy, hormone therapy

How can passing blood in urine be prevented?

Some causes of bloody urine can be prevented while others cannot. Preventable causes of blood in urine include:

1. Drinking adequate water – reduces the risk of stone formation in the urinary tract
2. Reduction in salt and sugar intake – reduces the risk of kidney failure
3. Maintenance of healthy weight – reduces the risk of kidney failure
4. Discontinuation of smoking – reduces the risk of kidney failure
5. Proper cleaning of the anus after passing stool (front to back for women) – reduces the risk of UTI.